Conventionally, shoe uppers are formed by assembling numerous components, which is a labor-intensive and expensive process. In order to improve the efficiency of shoe manufacturing, efforts have been made to automate this process.
For example, in certain cases, conventional shoe materials, such as leather, have been replaced by plastic materials, which can be molded into a particular shape using known vacuum forming techniques. In many cases, however, the three-dimensionally formed plastic piece often lacks flexibility which makes the resulting shoe uncomfortable to wear.
To address the comfort issue, attempts have been made to include a cushioning liner or other soft material between the plastic layers that are then vacuum formed together to form the three-dimensional part. However, because the cushioning layer is not in direct contact with the wearer's foot, the plastic molded shoe continues to lack the desired comfort and flexibility.
In some cases, a cushioning liner may be attached in the inner surface of the three-dimensionally molded part, but this additional step diminishes the efficiencies gained from vacuum molding by re-introducing manual labor back into the manufacturing process.
Furthermore, even though vacuum forming may automate certain aspects of the process, the vacuum forming process typically requires additional manual steps to place the materials into the mold and to remove each material from the mold.
As a result, it may be desirable to provide a manufacturing method that improves manufacturing efficiency by vacuum forming articles of wear as a single piece in a manner that does not introduce new manual steps into the process, while also producing articles of wear that have the desired amount of flexibility and comfort.